Plug receptacle by R-600 headlight for a block heater ?

[Mikesbucketlistmack]

I just bought my first Mack, a 1981 single axle R611ST dump truck. It was a former municipal truck. Next to the driver's headlight is a plug receptacle which I've been told by my step-Dad, a former Mack owner,is for an engine block heater. I opened the hood, and apparently it had been disconnected from the receptacle. Is the connection to the block heater on the upper part of the engine block on the driver's side ? I found what looks like a metal pad with three wire connections on it. If a connect a section of 3 conductor electrical wire to the receptacle, to which terminal on the engine block connection do I connect the black and white wires ? I can see where the ground was because when they cut it off part of the green wire is still there. Thank you !

[Lmackattack]

Most block heaters were installed in the freeze plug on the drivers side. Early block heater plugs were just hanging down near the battery box. Later they moved them to the headlight panel. If the old heater went out they may have put a pad on it similar to a pan heater?

[Maddog13407]

more than likely disconnected because its defective or shorted out... may need to put a whole new heater element in the block.

[j hancock]

Pretty sure it doesn't make any difference which is black or white for wiring it up.

I know that there is the correct way to wire with ground, neutral and power but for this it should be ok.

As mentioned, more than likely you will find that it is junk and will have to be replaced. I would probably do a quick wire up and test it with some jumper wires to see if it works before you wire it up to the headlight panel.